Abstract
Thin Bi films were simultaneously deposited by ultrahigh vacuum evaporation technique on three different substrates: GaAs, sapphire, and quartz. The effect of the substrate on the film microstructure was evaluated. Structural and morphological characterization of these as-deposited Bi films was performed using high resolution X-ray diffraction and scanning electron microscopy. X-ray diffraction analysis revealed the polycrystalline structure of all films with the predominant [003] orientation. The effect of the substrate on the structural quality of Bi films was investigated. Physical parameters such lattice constants, texture coefficient, effective crystallite size, dislocations density and strain were evaluated and widely described. The microscopy images clearly showed a granular structure corresponding to the grain formation on all surfaces of the Bi samples. The density, size, and shape of Bi grains varied greatly depending on the substrate material. Optical measurements of spectral reflectance and spectroscopic ellipsometry were also carried out to confirm the structural characteristics. We associated the different quality of the Bi films with the structure and chemical properties of the substrate.